Weft thread inserting device for shuttleless looms



N. KOKKINIS Oct. 17, I967 2 Sheets-Sheet 1 Filed Dec.

INVENTOR NIKOLAUS KOKKINIS ATTORNEY Oct. 17, 1967 N. KOKKINIS 3,347,284

WEFT THREAD INSERTING DEVICE FOR SHUTTLELESS LOOMS Filed Dec. 29. 1965 2 Sheets-Sheet 2 Ln 2 u.

0' E INVENTOR NIKOLAUS KOKKINIS BY W $4M ATTORNEY United States Patent Ofiice 3,347,284 Patented Oct. 17, 1967 3,347,284 WEFT THREAD INSERTING DEVICE FOR SI-IUTTLELESS LGOMS Nikolaus Kokirinis, Eriskirch, Germany, assignor to Lindauer Dornier Gesellschaft m.b.H., Liudau (Bodensee), Germany, a limited liability corporation of Germany Filed Dec. 29, 1965, Ser. No. 517,236 Claims priority, application Germany, May 22, 1965, L 50,782; Aug. 13, 1965, L 51,357 13 Claims. (Cl. 139-422) ABSTRACT OF THE DISCLOSURE At least one freely rotatable roller guide which carries a weft thread, after it has been removed from a supply spool, and introduces the same into a shed is mounted on the gripper part of the device which draws the weft thread from the supply spool. The roller guide includes a rotatable body for receiving and reversing the weft thread, which body is mounted on the inserting device and is supported on bearings.

This invention relates to a device for inserting weft threads in shuttleless looms, the device including a reciprocating gripper system in which weft threads are taken from supply spools in the form of loops, the supply spools being mounted on stationary parts of the loorn.

Constructions are known in which the weft thread is introduced into the shed by means of one or several gripper rods. In this system, the weft thread also is taken from supply spools mounted on either one or both sides of the shed separately from the gripper. In one known construction, gripper rods mounted on both sides of the shed are introduced into the center of the latter, one of which rods guides the weft thread to the center of the shed and there transmits it to the second gripper which latter, in turn, introduces the weft thread into the second half of the shed. In this type of insertion, it is also customary to introduce the weft thread, removed from the supply spool, in the form of a hairpin. Also in this case, a reversal of the weft thread will occur, particularly by the transmitting part of the gripper and, as a result, the weft thread being held, on one hand, and being removed from the supply spool, on the other hand, will travel at double the speed of introduction over a part of the transmitting member, for example the end of a transmitting groove. The high introduction velocity at which the weft thread passes or travels through the transmitting groove, leads, on the one hand, to a high wear and tear of the contact or bearing surface which is made, for this reason, rom a particularly wear-resistant material and, on the other hand, to an impermissible stress on the weft thread to be introduced. Such a high stress on the thread will considerably reduce the resistance to tearing or breaking of the threads, for example when weaving wool or cotton threads due to the heat thereby formed, and will result in increased thread breakage. This adverse effect is further increased by the temporary relatively great looping of the weft thread about the guide of the transmitter part. Another factor to be considered is the stress on the weft thread when it is drawn off of the supply spool, taking into account the relatively large mass of the latter and the required thread brake for eliminating the formation of snarls. The weaving of artificial fibers is extremely difficult because of the aforementioned heat, which produces changes in the structure of such threads and thereby increases the likelihood of breakage thereof. Such heat can be controlled only by reducing the operating speed of the machine.

The present invention eliminates the disadvantage and drawbacks of known constructions and provides a guide for the weft thread which has as little friction as possible, particularly on the transmitting part of the transmitting element, thereby considerably reducing both the wear and tear of the contact or bearing surface of the transmitting part and the stress and strain on the weft thread itself.

The friction between the weft thread and the guiding part of the transmitting member is reduced to a minimum in a very simple manner by the construction of the present invention and breakage of the weft threads is substantially eliminated.

The grippers of the device of the present invention include a tip having an inclined guiding edge as well as a hook which is open toward the warp threads and is covered by a resilient means.

In heretofore known devices, the hooks of the grippers for receiving or taking up the weft thread from a supply spool mounted on a stationary part of the loom are so constructed that the hook opening points in the direction of the warp threads. Due to this construction, the weft thread removed from the supply spool and introduced into the shed by the gripper, i.e., the upper and lower weft thread strand, is clamped in between the gripper rod, on the one hand, and the shed, on the other, which produces a considerable amount of friction and exerts a resulting stress on the weft thread.

In order to avoid such clamping of the weft thread in the shed, it has been proposed to construct the gripper hooks in a manner such that the weft threads will be positioned to the side of the gripper and, thus, may be inserted without actually making contact with the shed.

Such a construction, however, requires that the gripper hooks be open in the direction of the warp threads of the upper and lower shed, respectively, which results in the disadvantage that the spring means closing off the gripper hook opening in a resilient manner can not reject undivided warp threads. If undivided warp threads positioned transversely to the direction of movement of the grippers get into the gripper hook, such warp threads are torn and serious flaws are produced in the fabric to be made.

The present invention also eliminates the disadvantages held in readiness for the gripper hooks assumes an inclined position, with respect to the direction of movement of the grippers, at an acute angle. The gripper has a raised portion or elevation, with a rejecting edge, mounted thereon at the side of the covering spring and projecting beyond the spring in the direction of the upper and lower shed, respectively, the raised portion or elevation being mounted on that side of the covering spring which, before the weft thread is taken up by the gripper hook, faces the part of the weft thread being offered which is turned away from the gripper tip. With the aid of the raised portion or elevation formed at the gripper tip, undivided warp threads are guided past and over the springy closure of the gripper hook opening so that the warp threads can not get into the latter. The undivided warp threads are lifted over and beyond not only the gripper tip and the gripper itself, but also the gripper rod and, thus, can not be broken. Since the warp threads can no longer be broken by the gripper hook constructed in accordance with the present inven- H tion, any flaws which are Theinvention will be further illustrated by reference to the accompanying drawings in which:

FIGURE 1 is a top plan view of two cooperating gripper heads in one operating position thereof,

FIGURE 2 is a side view of one of the gripper heads shown in FIGURE 1,

FIGURE 3 is a partial longitudinal sectional view, at an enlarged scale, of a detail of the weft thread guide on the gripper heads,

FIGURE 4 is a partial longitudinal sectional view of a portion of FIGURE 3, at an enlarged scale, and showing a further construction of the gripper arms,

FIGURE 5 is a side view of a modified form of gripper head according to the present invention,

FIGURE 6 is a top plan view of the gripper head of FIGURE 5, and

FIGURE 7 is a front view in elevation of the gripper of FIGURE 5.

Referring to the drawings, FIGURE 1 illustrates the grippers of the shuttleless loom in one operative position thereof with respect to each other. The loom is one in which both grippers operate in opposite directions with respect to each other and alternately receive the weft thread from one of the supply spools mounted on both sides of the shed and transmit the weft thread in the center of the shed to the returning gripper.

Reference numerals 2 and 2, respectively, designate the gripper heads which travel from both sides of the shed oppositely to the center 4 of the comb, the gripper heads having the same shape and construction but being pivoted through 180 with respect to each other. Both gripper heads 2 and 2', respectively, are mounted on gripper rods 5 and 5', respectively, the operative connection of the gripper rods with the loom drive not being specifically illustrated. Each of the gripper heads 2 and 2', respectively, consists of a transmitting part 7 and 7', respectively, and a receiving part 8 and 8', respectively. The transmitting parts 7 and 7, respectively, have the function of receiving and drawing off, respectively, the weft thread 10 from the corresponding supply spool 9 and of transmitting it to the second gripper. The reception of the weft thread from the other gripper, in the center 4 of the comb, is effected by means of the receiving parts 8 and 8', respectively. For this purpose, each gripper head 2 and 2' is constructed in a bifurcated manner and a slot 12 and 12', respectively, extending in the axial direction of the gripper, is thereby produced between the two arms 13, 14, and 13', 14', respectively, for the engagement of the receiver hook 15, 15, respectively, of the other gripper. The arms 13, 14, and 13', 14', respectively, are each provided with a transmitting slot 17 and 18, respectively, extending in the longitudinal direction and in the direction of movement of the grippers. The transmitting slot 17 of the arm 13 is partially formed in a projection 20 and 20', respectively, on the arms 13 and 13', respectively, and each projection 20 and 28, respectively, includes a bore 22 and 22, extending through the transmitter slot 17 for receiving a needle bearing 21 and 21, respectively, which hearing has an axis of rotation perpendicular to the transmitter slots 17 and 18. The weft thread 10 removed from the supply spool is reversed by the surface of the outer race of the needle bearing 21 and 21, respectively, and is guided diagonally over the slot 12 and 12, respectively, by means of the transmitter slots 17 and 18.

As shown in FIGURE 3, the bores 22 and 22', respectively, are provided in the arms 13 and 13, respectively, for receiving the needle bearing 21 and 21', respectively, and rigidly inserted into each of these bores is a pin 31 forming the inner race of the needle bearing 21 and 21, respectively. The expanded part of the bore 22 serves to receive the outer race 34 of the bearing, which is freely rotatable on the pin 31 and is supported by the needle bearings 32. An abutment constituted by a screw 39 is threaded into the expanded portion of each bore 22 and 22' having the internal thread 38. The outer race 34 of the needle bearing 21 and 21', respectively, has the general shape of a cylinder open at one end and the closed end of the cylinder is received between two concentric pivot points or bearings 40 and 41, one of which is provided on the pin 31 and the other on the abutment 39, and an axial positioning of the outer race 34 as well as the needle bearings 32 is thereby established.

As shown in FIGURE 4, an annular groove 44 and 44, respectively, having a semi-circular cross-section and serving to guide the weft thread 10 may be provided in the outer race 34 and 34', respectively, and this annular groove should have approximately the same width as the transmitter slot 18. By means of such an annular groove, running of the weft thread 10 against the sides of the transmitter slots 17 and 18, and friction resulting therefrom, can be effectively prevented. It also has been found advantageous to provide the transmitter slot 18, in the arm 14 adjacent the roller guide 21 in an axial direction and in the direction of movement of the gripper, sufficiently deep that the weft thread 10 traveling or running over the outer race 34 and the end surface 45 and 45', respectively, of the transmitter slot 18 and 18, respectively, will assume a position which is inclined with respect to the direction of movement of the grippers. As a result of this construction, an improved transmission of the weft thread from one gripper to the other is obtained and the formation of snarls in the weft thread portion being guided by the roller guide to the transmitter slot 18 by way of the slot 12 is effectively eliminated. Moreover, the weft thread undergoes at the end of the transmitter groove 18 only a relatively minor deflection so that the danger of thread breakage at this point is substantially reduced.

The operation of the device of FIGURES 1 to 4 is as follows: when the gripper head 2 has arrived at the end position thereof outside the shed, during a subsequent displacement in the direction of the shed, the weft thread 10 being offered is received or taken up by the transmitter slots 17 and 18, at which time the weft thread will be positioned on the surface of the outer race 34 of the needle bearing 21. With the continued displacement of the gripper towards the center of the comb, the weft thread 10 will come to rest against the end surface 45 of the transmitter groove 18 and, due to the fact that the end surface 45 is set back or offset with respect to the outer race 34 of the roller guide 21, it will assume a position which is inclined with respect to the direction of movement of the gripper. Due to the weft thread 10 being retained on one side by suitable means, not shown, and by withdrawing the thread from the supply spool, as will as reversing it on the other side, the part of the weft thread being withdrawn from the supply spool has a movement imparted thereto corresponding to the displacement velocity of the gripper and with this speed it will roll off on the outer race 34. The roller guide 21 for receiving the weft thread 10 makes possible a reduction of the friction at that point of the gripper at which the weft thread contacts the gripper, thereby largely eliminating the formation of heat, which is damaging to the weft thread. Since, in the construction of the present invention, each of the two grippers takes the weft thread from one of the supply spools 9 and 9, respectively, being coordinated therewith, and conveys it to the center of the comb, the roller guide of each gripper will always rotate in the same direction so that, after delivering the weft thread to the other gripper and after again receiving the weft thread from the supply spool assigned thereto, neither a braking nor a change in the direction of rotation need take place. There will be, therefore, no friction at all or only an insignificant amount thereof between the roller 34 still rotating in the original direction and the weft thread to be taken off or received from the supply spool. The transfer or transmission of the weft thread 10 from the transmitting part 7 of the gripper 2 in the center of the comb is now effected by the engagement of the receiver hook 15 of the gripper 2' into the slot 12 of the gripper 2. The weft thread is inserted into the second half of the shed by the gripper hook 15 of the gripper 2. FIGURE shows, in a dotted line, the position of the weft thread after the reception thereof by the gripper hook of the gripper 2. p 7

Referring to FIGURE 5, the gripper head 2 has a gripper tip 46 with a guiding edge 47 which is inclined with respect to the direction of movement of the gripper. The grip er tip includes the gripper hook 48 which constit'utes the receiving portion 8 and the opening 50 of which faces the warp threads 51 and 52, respectively, of the upper and lower shed, respectively. The hook opening 50 is covered in an elastic manner by a laminated spring 53. Mounted at the gripper tip in the direction of the gripper displacement is an edge 54 of a raised portion or elevation 55 which extends at a steeper inclination as compared to the guiding edge 47 and the greatest difference in elevation thereof compared to the guiding edge 47 is adjacent the springy or movable end of the covering spring 53. The guiding edge 47, thus, extends over and beyond the range or area of the warp threads in the closed shed position so that the gripper tip is passed along below the warp threads in the closed shed position and the edge 47 receives undivided warp threads. The warp threads being thus received glide over the edge 47 and simultaneously over the edge 54 of the raised portion or elevation 55.

In FIGURE 7 of the drawings, an undivided warp thread 51 and 52, respectively, of the upper and lower shed, respectively, is shown in dashed-dotted lines. The dashed line illustrates the running up of an undivided warp thread 51 and 52, respectively, on the rejecting edge 54 of the raised portion or elevation 55. Also shown in FIGURE 6 in dashed-dotted lines is the second gripper in the position thereof shortly prior to receiving the weft thread by means of the gripper hook 48 and it has been assumed here that the weft thread was removed from or taken from a supply spool, not shown, by the gripper indicated in phantom in dashed-dotted lines.

The operation of the device is as follows: by means of the gripper 2, and the transmitting slots 17 and 18, the weft thread is removed from a supply spool during the movement of the gripper in the direction toward the shed and introduced into the latter. Undivided warp threads will then ride up on the guiding surface 47 of the gripper tip 46. The undivided warp threads being positioned at a right angle to the movement of the grippers will also arrive on the elevation or raised portion 55 and the edge 54 at the gripper tip and are guided by the edge 54 over the springy or movable end 56 of the-spring 53 which closes off the receiver hook 48 and will slide along the gripper and the gripper rod 5 without being torn oif. During the return movement of the gripper from the shed, the undivided warp threads will again slide over the gripper rod and will assume the closed shed position after retraction of the gripper rod f om the shed. Any tearing of the warp threads by the receiver hook 48 is thereby effectively prevented.

The weft thread being positioned in the transmitting slots 17 and 18, respectively, at an acute angle relative to the direction of movement of the gripper can, however, pass under the springy or elastic end 56 of the covering spring 53, which projects beyond the guiding edge 47 by a small amount, and can be taken up by the gripper hook. Due to this angular position of the weft thread 10, the latter rests, on the one hand, against the edge 54 of the raised portion or elevation 55 and, on the other hand, against the further downwardly positioned guiding edge 47, thus assuming a position with respect to the undivided warp threads which permits threading of the weft thread under the springy or elastic end 56 of the covering spring 53. The construction of the gripper of the present invention may be used in looms of the type described above having two grippers penetrating into the shed as well as in looms having only one gripper extending through the entire shed. The weft thread 10 is positioned completely freely during the introduction thereof into the shed and can not possibly be clamped in between the gripper rod and/ or rods and the shed.

It will be obvious to those skilled in the art that many modifications may be made Within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.

What is claimed is:

1. A weft thread inserting device for a shuttleless loom in which weft threads are withdrawn from supply spools and inserted in the form of loops into warp sheds, which comprises a pair of reciprocatable grippers and a freely rotatable roller guide mounted on each of the grippers for guiding a weft thread part way through a warp shed during its insertion into said shed.

2. A device according to claim 1 in which the roller guide comprises a rotatable body member supported by bearings.

3. A device according to claim 1 in which each of the roller guides are mounted on transmitter parts of the respective gripper and comprise an outer race of a needle bearing supported on bearing needles.

4. A device according to claim 3 in which the needle hearing has an inner race consisting of a pin mounted in the transmitter part of the gripper.

5. A device according to claim 4 in which the outer race has the general shape of a cylinder open at one end and the closed end is engaged by oppositely-acting pivot points.

6. A device according to claim 2 in which the rotatable body member has a serni-circular groove in the periphery thereof for receiving and guiding weft thread.

7. A device according to claim 1 in which each gripper has an arm on one side thereof having a transmitter slot therein, said slot having its end offset with respect to the roller guide, whereby a weft thread passing around the roller guide and through the slot is inclined to the direction of gripper displacement.

8. A device according to claim 1 in which each gripper has a tip having an inclined guiding edge, a hook open towards the warp threads for receiving and carrying the weft thread the remainder of the way across said shed, resilient means covering the hook, and rejecting edge means mounted at the gripper tip beside the resilient means and projecting vertically beyond the latter.

9. A device according to claim 8 in which the reject ing edge means is mounted on that side of the resilient :means which is remote said arm.

10. A device according to claim 8 in which the resilient means is a spring.

11. A device according to claim 8 in which the rejecting edge is formed with a surface having a steeper inclination' than the inclined guiding edge.

12. A device according to claim 11 in which the resilient means is a spring fixedly mounted at one end and disposed so that the greatest diiference in elevation between the rejecting edge and the inclined guiding edge is at its opposite and movable end.

13. A device according to claim 12. in which the movable end of the spring projects beyond the inclined guiding edge in the direction of insertion of the gripper.

References Cited UNITED STATES PATENTS 1,620,723 3/1927 Gabler 139122 1,883,354 IO/1932 Dreyfus et al. 139122 3,034,539 5/1962 Brown et al. 139122 3,081,797 3/1963 Flamand 139---122 3,210,881 10/1965 Wilson 242157 3,299,910 1/1967 Flamand 139122 MERVIN STEIN, Primary Examiner.

HENRY S. JAUDON, Examiner. 

1. A WEFT THREAD INSERTING DEVICE FOR A SHUTTLELESS LOOM IN WHICH WEFT THREADS ARE WITHDRAWN FROM SUPPLY SPOOLS AND INSERTED IN THE FORM OF LOOPS INTO WARP SHEDS, WHICH COMPRISES A PAIR OF RECIPROCATABLY GRIPPERS AND A FREELY ROTATABLE ROLLER GUIDE MOUNTED ON EACH OF THE GRIPPERS FOR GUIDING A WEFT THREAD PART WAY THROUGH A WARP SHED DURING ITS INSERTION INTO SAID SHED. 